There are various mounting devices for a cutting tool for mounting a cutting insert to a tool body by using a tightening screw. The mounting device exemplified here refers to a mounting structure having a screw hole with which a tightening screw inserted into a through hole of the cutting insert can be threadedly engaged with in an insert mounting seat of the tool body.
In PTL 1, for example, a cutting tool is disclosed that, in the insert mounting seat having a bottom wall surface and two side wall surfaces, the cutting insert is detachably fixed by screwing the tightening screw into a screw hole of the bottom wall surface through the through hole of the cutting insert. In a mounting device of this cutting tool, a central axis of the screw hole in the bottom wall surface of the insert mounting seat is inclined with respect to a normal direction of the bottom wall surface. If the central axis of the screw hole is inclined as described in PTL 1, by screwing the tightening screw into the screw hole in the bottom wall surface through the through hole of the cutting insert, the cutting insert can be pressed on the side wall surface side of the insert mounting seat.
On the other hand, in a mounting device for the cutting tool for fixing the cutting insert by using the tightening screw, such a mounting device is also known in which a screw hole is formed by shifting the central axis of the screw hole corresponding to the tightening screw in parallel with the side wall surface side of the insert mounting seat with respect to the central axis of the through hole of the cutting insert. When the central axis of the screw hole of the insert mounting seat is formed being shifted with respect to the central axis of the through hole of the cutting insert as above, the cutting insert can be pressed onto the side wall surface side of the insert mounting seat by tightening the tightening screw.